Substance dualism, that most unpopular of current theories of mind, continues to find interesting and able defenders.1 I shall focus on one set of arguments supplied by one of the current defenders, and I shall argue that these arguments fail. That in itself is a matter of some interest, since it is always reassuring to be able to demonstrate that unpopular doctrines are rightly unpopular. But I hope that a further interest will attach to the refutation, in that it will invoke some relatively unfamiliar thoughts about the nature of perception